Recently, virtual network systems such as NFV (Network Functions Virtualization) have been proposed to build network environments. Virtual network systems allow virtual devices implemented in physical devices to carry out processing as network devices, thus realizing virtualization of networks. Hereinafter, virtual devices for executing processing as network devices will be referred to as virtual network devices.
Patent Literature 1 discloses a technology specifying fault locations causing faults based on fault information detected by multiple network devices in a physical network system.